1. Field of the Invention
The present invention relates to a method for producing L-lysine by fermentation.
2. Description of the Prior Art
L-lysine, which is used as a feedstuff is normally produced industrially by a fermentation process in which L-lysine producing mutants of the genus Brevibacterium or Corynebacterium are used. Various L-lysine-producing mutants, produced by the artificial mutation of wild strains of microorganisms of the genera Brevibacterium and Corynebacterium, are known. Examples of such artificial mutants are mutants resistant to S-(2-aminoethyl)-cystein (hereinafter identified as AEC), mutants requiring L-amino acids such as L-homoserine, L-threonine, L-leucine, or L-methionine for their growth (Japanese Published Examined Patent Application Nos. 28078/1963, 26639/1977, 28677/1973, U.S. Pat. Nos. 3,707,441 2,979,439), mutants resistant to AEC and further requiring an amino acid such as L-leucine, L-homoserine, L-proline, L-serine, L-arginine, L-alanine or L-valine (Japanese Published Examined Patent Application Nos. 36888/1974, 210787/1976, 34836/1979, 1040/1980, U.S. Pat. Nos. 3,708,395 and 3,825,472), L-lysine-producing mutants resistant to .alpha.-amino-lauryllactam, aspartic acid-analogs, sulfa drugs, quinoids, N-lauroyl leucine, or to inhibitors of oxalacetate, decarboxylase or respiratory system enzymes (Japanese Published Unexamined Patent Application Nos. 31093/1975, 102498/1977, 9394/1978. 86089/1978, 9783/1980, 9759/1980, 32995/1981, 39778/1981, Japanese Published Examined Patent Application Nos. 43591/1978, 1833/1978), l-lysine-producing mutants requiring inositol or acetic acid (Japanese Published Unexamined Patent Application Nos. 9784/1980, 8692/1981), and L-lysine-producing mutants sensitive to fluoropyruvic acid or to a temperature more than 34.degree. C. (Japanese Published Unexamined Patent Application Nos. 9783/1980, 86090/1978). A need continues to exist, however, for a method by which L-lysine can be produced in greater yields by fermentative techniques.